The invention is concerned with a process for accelerating the hardening of joints glued with crystalline hardening adhesives, according to which the materials to be joined are coated with adhesive, heated for the purpose of driving off the thinner and joined together. Glued joints, for example, between leather, wood, metallic foils, plastic or synthetic rubber are produced in that the materials are coated with adhesive and pressed together.
One differentiates, thereby, between amorphous and crystalline hardening adhesives. The present invention is concerned only with crystalline hardening adhesive, for example, polyprene and neoprene.
Such adhesives are quite viscous and are therefore diluted with a thinner. After application of the adhesive, the thinner must be removed again before joining the materials together. This occurs because the thinner is driven out by heating the material which is coated with the adhesive to 100.degree. C. Subsequently, the materials are glued together by pressing them together. As a result of prior heating, the initial adhesion of the glued joint is relatively small. It takes about 2 to 3 days until the adhesive is completely crystallized and maximum adhesion of the glued joint is attained.
The hardening is, however, often incomplete, so that even after several days, the required minimum adhesion is not attained. This is particularly the case with warm ambient temperatures, for example, on hot summer days, although not confined thereto. Such joints are unusable and represent thereby a considerable loss.